Electrical steering system for boats

ABSTRACT

There is disclosed a control system for electronically controlling a boat powered by a conventional twin screw inboard-outboard drive system. The boat is maneuvered by a plurality of reversible direct current motors which are controlled through a complex electronic circuit system by a portable control box. The portable control box is disengageably connected to the electronic system so that the boat may be maneuvered from any position thereon.

llite States Patent Norton [4 a1". 2%, 1972 [s41 ELEETRICAIL STEERINGSYSTEM FOR 2,498,223 2/1950 Rommel ..114/144 BQATS 3,013,519 12/1961Wiggermann 3,187,704 6/1965 Shatto, Jr. et al..... I 1 Inventor CalhounNam, mm 3,481,299 12/1969 Horn ..114/144 3 "l ['7 A1 gnee Aron Controls,lac Evanston 111 Primary Examiw Mflmn Buckle: [22] Flled: Apr- 6, 1Assistant Examiner-CarlA. Rutledge [211 App! No 25 874 Attorney-Olson,Trexler, Wolters & Bushnell [57] ABSTRACT 'i l There is disclosed acontrol system for electronically con- [58] Fieid 8 E 34 trolling a boatpowered by a conventional twin screw inboard- -outboa.rd drive system.The boat is maneuvered by a plurality of reversible direct currentmotors which are controlled through a complex electronic circuit systemby a portable con- [56] References Cited trol box. The portable controlbox is disengageably connected UNITED STATES PATENTS to the electronicsystem so that the boat may be maneuvered from any position thereon.2,804,838 9/1957 Moser ..115/18 2,877,733 3/1959 Harris ..115/18 7Claims, 6 Drawing Figures This invention relates generally to a controlsystem for maneuvering a boat, and more particularly to an electroniccontrol system for maneuvering a boat.

In the past, steering arrangements for boats were disclosed inaccordance with my own U.S. Pat. No. 3,294,054 which shows amechanically coupled steering system without the use of electroniccontrols. Although the system therein disclosed provides an excellentsteering mechanism for facilitating maneuvering of the boat, it has beenfound that by utilizing an electronic control system, as disclosedhereinafter, the ability to maneuver a boat is enhanced. It has alsobeen found that boat maneuverability can be controlled from any positionon the boat whereas such a feat is not possible to utilizing amechanically coupled system by itself.

Accordingly, a general object of the present invention is to provide anovel electronic control system for maneuvering a boat.

Another object of the present invention is to provide an electroniccontrol system for maneuvering a boat wherein maneuvering can beaccomplished from any desired position.

A more specific object of the present invention is to provide anelectronic control system for controlling the maneuverability of a boatwherein the clutch, throttle, and steering mechanism of the drive systemcan be independently regulating from various remote positions.

A further object of the present invention is to provide novel electroniccontrol circuits for the control of the clutch, throttle and steeringmechanisms of a boat drive system.

Other objects and advantages of the present invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a block diagram of the electronic control system forcontrolling the maneuverability of a boat powered by a twin screwinboard--outboard drive system;

FIG. 2 is a block diagram of the electronic control circuit forcontrolling the throttles and steering of the boat;

FIG. 3 is a schematic diagram of the electronic control circuit forcontrolling the steering of the boat;

FIG. 4 is a schematic diagram of the direct current reversible motorsused in conjunction with the electronic control circuit of FIG. 3 forcontrolling the steering of the boat;

FIG. 5 is a schematic diagram of the electronic control circuit anddirect current reversible motor for controlling the throttles of theboat; and,

FIG. 6 is a schematic diagram of the electronic control circuit anddirect current reversible motor for controlling the clutch mechanisms ofthe boat.

Referring now more specifically to the drawings and particularly to FIG.1, the rear end section of a boat 10 is shown, conventionally powered bya twin screw inboard--outboard drive system designated generally by thenumerals 12 and 14 although it is to be understood that conventionaloutboard engines could also be used. An electronic control systemdesignated generally by the numeral 16 electronically controls themaneuverability of the boat 10 in the same manner as the boat disclosedin my patent, U.S. Pat. No. 3,294,054, is maneuvered but with a higherdegree of accuracy. For a discussion of the particular maneuveringpositions and the various forces required for these respectivepositions, reference is made to the above mentioned patent.

The inboard--outboard drive system 12 is positioned on the left or portside of the boat and includes an engine 18 mounted within the boatproviding the power for a port outboard drive unit 20 conventionallymounted on the boat transom at the rear or stem of the boat. A movablethrottle arm 21 cooperates with the engine 18 for varying the poweroutput of the engine from no power or idle power when the throttle armis in the position as indicated in solid lines to full power when thethrottle arm is positioned as indicated in dotted lines.

boat transom. A tiller or steering lever 24 is provided for swinging thedrive unit to the left or right about a generally vertical pivot 26, asviewed in FIG. 1, to change the angle of The outboard drive unit 20includes a propeller 22 mounted v on the end of a propeller shaft (notshown) which extends in a generally horizontal position rearwardly withrespect to the thrust of the propeller with respect to a longitudinalaxis 23 of the boat. The extreme positions, both left and right, of theoutboard drive unit 20 are indicated by dotted lines in FIG. ll. Anengageable clutch member 30 is provided for engaging and disengaging theengine 18 and outboard drive unit 20. As indicated in FIG. 1, the clutchcan be positioned to the far left for engaging the engine and outboarddrive unit wherein the propeller 22 is driven in one direction forproviding forward power to the boat 10. The propeller is driven in anopposite direction for providing rearward power to the boat 10 bypositioning the clutch member 30 to the far right and finally,positioning the clutch intermediate the two above described extremepositions disengages the motor and drive unit.

The inboard--outboard drive system 14 is positioned on the right orstarboard side of the boat and includes an engine ma mounted within theboat providing the power for a starboard outboard drive unit 20a mountedon the boat transom at the rear or stem of the boat. Theinboard--outboard drive system 14 is structurally or functionallyexactly the same as the inboard--outboard drive system 12 and thereforelike components are designated with like numbers with an additionalsuffix a indicating the components of the drive system 14.

The maneuverability of the boat 10 is dependent upon three factors,firstly, the physical positioning of the propellers 22 and 22a withrespect to the longitudinal axis 28 of the boat, secondly, the amount ofpower delivered by the engines 18 and 18a which is determined by thepositions of throttle arms 21 and 21a, and thirdly, by the directionpropellers 22 and 22a are driven which is dependent upon whether theclutches 30 and 30a engage their respective engine and drive unit in aforward or reverse manner. As stated above, reference can be made to mypatent, U.S. Pat. No. 3,294,054, for a detailed description of thevarious maneuvering positions utilizing these factors.

For each inboard--outboard drive system 12 and 14, the electroniccontrol system 16 provides a steering motor assembly 32 and 32arespectively, a throttle motor assembly 34 and 34a respectively, and aclutch motor assembly 36 and 360 respectively. The steering motorassemblies 32 and 32a control the positioning of their respective driveunits 20 and 20a as described in more detail hereinafter. The throttlemotor assemblies 34 and 34a are used to position their respectivethrottle arms 21 and 21a for controlling the power output of theirrespective engines 18 and 18a and the clutch motor assemblies 36 and 36aare provided for positioning their respective clutch members 30 and 30afor controlling the engaging status of their respective engine andoutboard drive units.

The electronic control 16 also includes electronic control circuitry,described in detail hereinafter, positioned within a control panel 38which may be mounted on boat 10 in any convenient location. The controlcircuitry is electrically connected to the above described motorassemblies via conduits 40 for controlling the motor assemblies asdescribed below. Additional electronic control circuitry co-operatingwith the circuitry within control panel 38 is located within a portablecontrol box 42. The control circuitry within the control box may bedisengageably connected to the control circuitry within control panel 38for co-operating therewith. This is accomplished by an electrical cordand plug 44 which cooperates with a socket 46 for connecting anddisconnecting the electronic circuitry in control panel 38 and portablecontrol box 42. This disengageable feature allows the operator of boat10 to maneuver the boat from any position thereon merely by supplying anappropriate extension cord (not shown) or if desired by providingadditional sockets located in various positions on the boat andconnecting the electronic circuitry within control panel 38 to thosesockets.

The steering motor assembly 32 includes a reversible direct currentmotor 48 and a piston assembly 50 mechanically coupled to the output ofreversible motor 48 for driving a piston or actuator 52 of the pistonassembly 50. The piston 52 is driven from a retracted position asindicated by solid lines in FIG. 1 to an extended position as indicatedin dotted lines when the reversible motor 48 is forwardly driven andback to its retracted position when the reversible motor is reverselydriven. It is to be understood that the reversible direct current motorand the piston assembly are both conventional and conventionally coupledto each other so as to provide the above described results and thereforewill not be discussed in further detail. The free end of piston 52 whichmay be a gear driven rack is mechanically connected to the steeringlever 24 of the port outboard drive unit 20 by means not shown so as todrive the outboard drive unit and corresponding propeller 22 from theextreme right as viewed in Fig. 1 when the piston is in its extendedposition to the extreme left when the piston is in its retractedposition.

A steering motor assembly 32a which is both structurally andfunctionally identical to the steering motor assembly 32 is mechanicallycoupled to the steering lever 24a of the starboard outboard drive unit20a in the same manner as steering motor assembly 32 is coupled tosteering lever 24. The reversible direct current motor, piston assembly,and actuator of the steering motor assembly 32a are designated bynumerals 48a, 50a, and 5211 respectively. It is to be noted that whenthe actuator 52a is in its extended position as indicated by dottedlines, the starboard outboard drive unit 20a and its correspondingpropeller 22a are positioned to the right as viewed in FIG. 1. This isidentical as that described with respect to port outboard drive unit 20.It is to be understood that the piston 52a may be easily coupled to thesteering lever 24a in such a manner so as to have the propeller 22apositioned to the left when the piston is in its extended position.

The throttle motor assemblies 34 and 34a are likewise structurally andfunctionally equivalent to the steering motor assembly 32, thereversible direct current motor, piston assembly, and actuator ofthrottle motor assembly 34 being designated by numerals 54, 56 and 58respectively while the reversible direct current motor, piston assembly,and actuator of the throttle motor assembly 34a being designated bynumerals 54a, 56a and 58:: respectively. The free end of piston 58 orrack is mechanically connected to the throttle arm 21 of engine 18 so asto drive the throttle arm 21 from its position as indicated in solidlines when the actuator is in its retracted position to a position asindicated in dotted lines when the actuator is in its extended position.As stated above, when the throttle arm is in its solid lined position,the engine 18 merely provides idle power and when the throttle arm is inits dotted lined position, the engine provides full power. It is to beunderstood that the engine power continuously increases as the throttlearm is driven from its solid lined position to its dotted linedposition. The actuator 58a is mechanically coupled to the throttle arm21a in the same manner for controlling the power output of engine 18a.

The clutch motor assemblies 36 and 36a are also both structurally andfunctionally identical to steering motor assembly 32 and includerespective reversible direct current motors 60 and 60a, piston or rackassemblies 62 and 62a, and actuators 64 and 64a. The free end ofactuator 64 is mechanically connected to the engageable clutch member 30for driving the clutch member from its far left position, as viewed inFIG. 1, when the actuator is in its retracted position to the far rightwhen the actuator is in its extended position and in an intermediateposition when the end of the actuator is intermediate its retracted andextended positions. As stated above these three clutch positionsrepresent forward engagement of the outboard drive unit 20 and engine18, reverse engagement, and disengagement. The actuator 64a ismechanically coupled to the engageable clutch member 30a so as toprovide the same function with respect to the inboard--outboard drivesystem 14 as actuator 64 provides with respect to inboard-- outboarddrive system 12.

Now that a sufficient description has been given of each componentrequired for maneuvering boat attention is directed to portable controlbox 42 for a discussion dealing with the control of each of the abovedescribed components for electronically controlling the maneuverabilityof boat 10. It is to be understood that each individual controlmechanism on portable control box 42 is appropriately connected to theelectronic circuitry required to control the various components asdescribed above and that this electronic circuitry will be described ingreat detail subsequently.

The portable control box includes a steering wheel 66 and a switch 67which may be referred to as a maneuvering switch. This switch is atwo-position switch, one position being the cruise position and theother position being the maneuvering" position. The steering wheel 66 isappropriately coupled to the electronic circuitry so as to drive thepistons 52 and 52a of steering motor assemblies 32 and 32a respectivelywhen the steering wheel is turned either clockwise or counterclockwiseas viewed in FIG. 1. This, of course, causes the outboard drive units 20and 20a respectively to pivot about venical pivots 26 and 26a.

When the maneuvering switch 67 is in the cruise position, the electroniccircuitry is such that the outboard drive units 20 and 20a arepositioned parallel to each other and remain parallel to each other whenthe steering wheel is turned. That is to say, for example, when thesteering wheel is turned clockwise the outboard drive units willconcurrently pivot to the right as viewed in FIG. 1 and will pivot tothe left when the steering wheel is turned counterclockwise.

When the maneuvering switch is flipped into the maneuvering position, aportion of the electronic circuitry is reversed as will be describedhereinafter. As a result, when the wheel is turned clockwise both of theoutboard drive units toe in, i.e., concurrently pivot towards eachother, and will toe in until they reach the maximum position which isabout 45 to the longitudinal axis 28 of the boat 10 or at about withrespect to each other. This will also be the position at which thesteering wheel can no longer be turned clockwise. When the steeringwheel is turned counterclockwise until it can no longer be so turned,the outboard drive units will toe out, i.e., concurrently pivot awayfrom each other until they reach their stop positions which again are atabout 45 angles to the longitudinal axis 28 and at about 90 with respectto each other.

The portable control box 42 also provides a pair of throttle levers 68and 68a which are appropriately connected to the electronic circuitryfor driving throttle arms 21 and 21a respectively when the throttlelevers are moved in a forward and rearward direction. Two clutch levers70 and 700 are also provided, appropriately connected to the electroniccircuitry, for driving engageable clutch members 30 and 30a respectivelyinto positions described above when the clutch levers are moved inupward and downward directions.

When the maneuvering switch is in the cruise position, the boat issteered and the throttles are actuated in the usual manner obtainingconventional but precise results. When the maneuvering switch is in themaneuvering position with the steering wheel turned clockwise as far asit can go so that both drive units are toed in, free maneuverability canbe obtained. In this condition and with both clutches engaged in theforward position, the boat can be steered merely by differentialoperation of the throttle levers 68 and 680. In other words, if theright hand or starboard throttle 70a is advanced relative to the portthrottle 70 so that engine 18a has greater output power than engine 18,the boat will turn to the right. As stated above, this is explained andbroadly covered in US. Pat. No. 3,294,054.

When the drive units are toed in and with one engine engaged in reverseand the other in forward, and with the throttle levers actuatedgenerally uniformly, the boat will turn about its center of drag. Inother words, the boat will turn completely around within its own length.The direction of turn can be reversed by a turn of the steering wheelcompletely counterclockwise so that the drive units are toed out.

An interlock, which will be described with respect to FIG. 6, isprovided between the throttle electronic circuitry and the clutchelectronic circuitry so that the clutches cannot be shifted until thethrottles have been returned to the idle position. In addition, a timedelay electrical device is provided so that if the clutch switches havebeen shifted from one position to the other while the throttles areadvanced no shifting will take place even when the throttles arereturned to the idle position until after a small time delay whichpermits the engines to drop back to the correct speed before actualshifting takes place.

It is to be noted that the above described control system is adapted tobe connected with the usual steering, throttle and gear shift controlsof conventional structures.

Turning to FIG. 2, a block diagram of the electronic control circuit forcontrolling the throttles and steering of the boat is shown. Anadjustable input circuit 72 is connected across a l2-volt direct currentpower supply (not shown) for developing a variable differential signal.In the case of the electronic steering circuitry the value of thisdifferential signal is dependent upon the position of steering wheel 66of FIG. 1 while in the case of the electronic throttle circuitry thedifferential signal value is dependent upon the position of throttlelevers 68 and 68a. This differential signal is fed to an operationalamplifier circuit 74 which both regulates and amplifies the differentialsignal. The output of the operational amplifier circuit, which isconnected to a switching circuit 76, is referenced to a positive 6 voltsand can swing either positive or negative from that value depending uponthe sign of the differential input signal.

When for example, the steering wheel is turned in one direction thedifferential input signal is increased thus swinging the output of theoperational amplifier circuit positive with respect to the abovementioned reference. When the steering wheel is turned in the oppositedirection, the differential input signal is decreased causing the outputof the operational amplifier circuit 74 to drop below the referencevoltage. The output of switching circuit 76 is electrically connected toa motor I assembly circuit 78 which in the case of the electronicsteering circuit includes the two reversible direct current motors 48and 4811. When the output of the operational amplifier circuit ispositive with respect to the 6 volts reference, the switching circuitallows the reversible motors to be forwardly driven for driving theoutboard drive units 20 and 20a in one direction as described withrespect to FIG. 1. When the output of operation amplifier circuit 74 isbelow the 6 volts reference, the switching circuit allows the reversiblemotors to be reversely driven for driving the outboard drive units in anopposite direction. As stated above, the switching circuit includes amaneuvering switch which can adjust the switching circuit so as to drivethe reversible direct current motors in opposite directions which causesthe outboard drive units to be either toed in or toed out as describedwith respect to FIG. 1.

Separate electronic control circuitry is provided for the throttles andfunctions in the same manner as described above except that each portionof the circuitry controls only one reversible direct current motorincluded in motor assembly 78, that motor being either reversible directcurrent motor 54 or 54a. When, for example, the throttle lever 68 isrepositioned this either increases or decreases the value of thedifferential input signal depending upon which direction the throttlelever was moved. This variation in the differential input signal in turneither increases or decreases the output of the operational amplifiercircuit with respect to its output reference voltage causing theswitching circuit to allow the reversible direct current motor 54 to bedriven in one direction or the other.

Turning to FIG. 3, a schematic view of an electronic control circuit 79for steering boat 10 is shown. The circuit includes a l2-volt directcurrent source 80, an adjustable input circuit 82 electrically connectedacross the power supply 80, an operational amplifier circuit 84electrically connected to the output of the adjustable input circuit,and a switching circuit 86 electrically connected to the output of theoperational amplifier circuit.

The adjustable input circuit 82 includes a master potentiometer R5 and aslave potentiometer R6 fonning a part of a bridge circuit 87 acrosspower supply 80. The adjusting arm 83 of potentiometer R5 ismechanically connected to the steering wheel 66 so as to be driven bythe steering wheel causing the voltage across R6 to vary when thesteering wheel causing the voltage across R5 to vary when the steeringwheel is moved which in turn drives actuators 52 and 52a as describedabove. Potentiometer R6 likewise has an adjusting arm 85 which ismechanically connected to the steering actuators 52 and 52a for varyingthe voltage across R6 in proportion to the movement of the actuators aswill be described hereinafter. Two resistors R1 and R2 connected inseries across power supply divide the 12 volts supply so that 6 voltsappear between resistors R1 and R2 and at the top of potentiometer R6which has one end electrically connected intermediate resistors R1 andR2. A resistor R7 having one end electrically connected to the otherside of potentiometer R6 with the other side of R7 connected to thenegative side of power supply 70 is provided so that the range ofvoltage appearing across potentiometer R6 is about 3 volts. The voltagerange of potentiometer R5 is also 3 volts or less depending upon theadjustment of potentiometers R3 and R4 which also form part of bridgecircuit 87. Each of the potentiometers R3 and R4 has a respectiveadjusting arm 86 and 83 electrically connected to a respective end ofpotentiometer R5. The potentiometers R3 and R4 are connected in serieswith the otherwise free end of potentiometer R3 electrically connectedintermediate R1 and R6 and the otherwise free end of potentiometer R4electrically connected through a resistor R19 to a point intermediateresistors R7 and potentiometer R6. Potentiometers R3 and R4 are used toadjust the range of travel of actuators 52 and 52a when potentiometer R5is moved from one extreme position to the other which in turn is drivenby moving steering wheel 66 as stated above. The slave potentiometer R6is mechanically connected to the actuator in such a way that only aboutthree turns of the lO-turn potentiometer are used for full range travelof the actuator. In other words, the adjusting arm will only move adistance equal to threetenths that of the entire distance ofpotentiometer R6 when the actuators 52 and 52a are moved from oneextreme position to the other as described with respect to FIG. 1.Therefore, about seven-tenths of the resistance of the potentiometer R6appears in the circuit as if it were a fixed resistance. Resistor R19 isprovided within the bridge 87 to match this unvarying portion ofpotentiometer R6. A resistor R8 has one end electrically connected tothe actuating arm 85 of potentiometer R6 and its otherwise free endconnected to the negative input terminal of an operational amplifier 90which will be described hereinafter. A resistor R9 electrically connectsthe adjusting arm 83 to the positive input terminal of operationalamplifier 90. The two resistors R8 and R9 are provided so as to utilizethe voltages across potentiometers R5 and R6 as a differential inputsignal which is to be fed to the input of operational amplifier 90.

The operational amplifier circuit 84 includes an operational amplifier90 having negative and positive input terminals respectively designatedby numerals 1 and 2, an output terminal designated by the numeral 3 andadditional terminals designated by the numerals 4, 5, 6 and 7respectively. The operational amplifier circuit also includes anadjustable resistor R10 connected at one end to the output terminal 3 ofthe operational amplifier 90 with its otherwise free end connectedintermediate resistor R8 and negative input terminal 1. The resistor R10provides conventional negative feedback for the operational amplifier.The amplifier gain is determined approximately by the values ofresistors R8 and R10. The operational amplifier 90 is a conventional RCANo. CA 3029 type amplifier and reference is made to the RCA handbook RCALinear Integrated Circuits (technical series IC-41) for a detaileddiscussion of the amplifier. It is to be understood, of

course, that other operational amplifiers providing the same function asdescribed below may be substituted therefor. A resistor R11 and acapacitor C2 connected in series, are provided to form a phasecompensation network for the operational amplifier. This series circuithas one end connected to terminal 4 of the operational amplifier and itsotherwise free end connected intermediate resistors R1 and R2. Theterminal 5 of the operational amplifier is connected to the otherwisefree end of resistor R11 and the terminal 7 is connected to the negativeside of power supply 80. The output of the operational amplifier isreferenced to a positive six volts as discussed below and can swingeither above or below that value depending upon the sign of thedifferential input signal. That is to say that the output of operationalamplifier depends upon whether the voltage across R9 is greater or lessthan the voltage across R8. A resistor R18 is electrically connected atone end intermediate resistor R9 and positive input terminal 2 of theoperational amplifier, the otherwise free end of resistor R18 beingconnected intennediate resistors R1 and R2. R18

has been included in the circuit for the sake of completeness. Inpractice, it has not been used and is not essential in this application.

The switching circuit 86 includes an NPN transistor Q1 and PNPtransistor Q2 each of which has its base connected to the output ofoperational amplifier 90 and its emitter connected to the emitter of theother transistor. The collector of transistor Q1 is connected to thepositive side of the power supply 80 through two biasing resistors R12and R13 while the collector of Q2 is connected to the negative side ofpower supply 80 through biasing resistors R14 and R15. The emitters ofboth transistor Q1 and Q2 are also connected intermediate resistors R1and R2 so that the emitters are maintained at six volts, the outputreference voltage ofthe operational amplifier 90 as referred to above.The second NPN transistor O3 is connected across the power supply 80with its base connected intermediate resistors R14 and R15, its emitterconnected to the negative side of the power supply, and its collectorconnected to the positive side of the power supply through anelectromagnetic relay K1. A second electromagnetic relay K3 is connectedacross the electromagnetic relay Kl. It is to be understood that theelectromagnetic relays herein referred to, are conventional relayshaving electromagnetic coils which when energized open or close normallyclosed or opened associated contact. When reference is made to the relayitself what is meant is the electromagnetic coil. A second PNP typetransistor O4 is also connected across the power supply 80 having itsbase connected intermediate resistors R12 and R13, its emitter connectedto the positive side of power supply 80, and its collector connected tothe negative side of power supply 80 through an electromagnetic relayK2. A fourth electromagnetic relay K4 is connected across relay K2. Theelectromagnetic relays K1, K2, K3 and K4 are also electrically tied to awafer type switch 92 which may be actuated by maneuvering switch 67 suchthat electromagnetic relay K3 is electrically connected across K2 andthat electromagnetic relay K4 is connected across K1 for reasonsdescribed below.

The transistor Q3 has a filtering circuit connected across its collectorand emitter comprising a capacitor C4 and resistor R17 connected inseries while the transistor 04 has a filtering circuit connected acrossits collector and emitter comprising capacitor C3 and resistor R16connected in series. The electromagnetic relays K1, K2, K3 and K4 haverespective contacts K1, K2, K3 and K4 which are electrically connectedto reversible direct current motors 48 and 48a and will be describedwith respect to Fig. 4.

The electronic control circuit 79 of FIG. 3 includes a capacitor C1electrically connected across the resistors R1 and R2 so as to prevent adrain of power from supply 80 when reversible direct current motors 48and 48a are initially energized as described below. A diode D1 havingits anode connected to the positive side of the power supply 80 and itscathode connected to the remainder of the electronic circuit 79 isprovided to block the discharging of capacitor C1 by the motor load. Italso protects the circuit against accidental application of the wrongpolarity.

In operation, when the steering wheel 66 is maintained such that theoutboard drive units 20 and 20a are positioned parallel to thelongitudinal axis 28 of boat 10 equal voltages appear acrosspotentiometers R5 and R6 causing a differential input signal of zero toappear at the input of operational amplifier 90. The emitters oftransistors Q1 and Q2 are therefore maintained at 6 volts referencecausing the transistors to be in a nonconductive state. This in turnprevents either of the transistors Q3 or Q4 from being in a conductivestate. As long as the transistors Q3 and Q4 remain in a nonconductivestate, the electromagnetic relays K1, K2, K3 and K4 remain in adeenergized condition which prevents the reversible motors 48 and 48afrom driving their respective outboard drive unit as will be describedwith respect to FIG. 4.

When, for example, the steering wheel 66 is turned clockwise the voltageacross potentiometer R5 increases causing the bridged circuit 87 to beunbalanced and thus a positive differential input signal appears at theinput of operational amplifier 90. This in turn increases the output ofthe operational amplifier with respect to its six volts referencecausing transistor O1 to conduct. With Q1 conducting, transistor 04 isproperly biased, allowing electromagnetic relays K2 and K4 to beenergized. As will be described with respect to FIG. 4, this causesreversible motors 48 and 48a to be simultaneously driven in forwarddirections so that their respective actuators 52 and 52a move toextended positions. The outboard drive units 20 and 20a will in turn bepivoted to the right as viewed in FIG. 1. When the steering wheel is nolonger turned, such that the voltage across potentiometer R5 ismaintained at a value greater than the voltage across potentiometer R6,the adjusting arm is repositioned by its mechanically connectedactuators 52 and 52a such that bridge circuit 87 is again balanced. Thisin turn drives the differential input signal to a value of zero causingthe reversible motors 48 and 48a to be de-energized.

Similarly, if steering wheel 66 is turned counterclockwise reducing thevoltage across potentiometer R5 a negative differential input signalappears at the input of operational amplifier 90 causing Q2 and O3 toconduct which in turn energizes electromagnetic relays K1 and K3 causingthe reversible motors 48 and 48a to be driven such that the outboarddrive units 20 and 20a are pivoted to the left as viewed in FIG. 1. Whenthe steering wheel is no longer turned, the potentiometer R6 is againrepositioned such that a differential input signal of zero appears atthe input of operational amplifier 90 causing the reversible motors tobe de-energized and stopping outboard drive units 20 and 20a.

Turning to FIG. 4, the reversible direct current motor 48 has itspositive or forward side connected to electromagnetic relay contact K2and its negative or reverse side connected to electromagnetic relaycontact K1. When the electromagnetic relays K1 and K2 are in theirde-energized state, the contacts K1 and K2 connect reversible motor 48to ground as indicated by a solid line representation in FIG. 4. Whenthe electromagnetic relay K2 is energized, the contact K2 is moved toits dotted line position. This connects the reversible motor 48 to al2-volt direct current source such that the motor is driven in a forwarddirection so as to function as described above. When the electromagneticrelay K1 is energized, contact K1 is moved to its dotted line positionsuch that the reversible motor 48 is driven in a reverse direction.Reversible motor 480 is electrically connected to a 12-volt DC powersupply in the same manner as reversible motor 48 such that motor 48a isdriven in a forward direction when electromagnetic relay K4 is energizedand in a reversed direction when electromagnetic relay K3 is energized.

The above discussion assumes that maneuvering switch 67 is in its cruiseposition. If the switch is thrown to its maneuvering" position causingelectromagnetic relay K3 to be connected to K2 and K4 to be connected toK1 the operation will be the same except that motor 48a will be drivenin an opposite direction from that of motor 48. This in turn will causea toeing in and toeing out of drive units 20 and 200 as described withrespect to FIG. 1.

It is to be understood that reversible direct current motors 48 and 480may utilize their own electronic control circuit 79 as described in FIG.3. In such a case, a potentiometer R of each circuit would bemechanically connected to the steering wheel 66 such that each of thepotentiometers actuating arms 82 would be moved equally andsimultaneously. It is to be further understood that the l2-volt directcurrent power supply 80 may be used to power the reversible motors 48and 48a in addition to the electronic circuitry of FIG. 3 rather thanusing separate power supplies as indicated in FIG. 4.

Turning to FIG. 5, an electronic control circuit for the throttle arm 21is shown. This circuit functionally and structurally is similar to thatcircuit disclosed with respect to FIG. 3 with exceptions indicatedbelow. Electrical components of the electronic circuitry of FIG. 5 whichare equivalent to those components of FIG. 3 are designated with likenumerals in addition to a suffix a.

The first electrical difference between the two circuits is thatpotentiometer R19 replaces resistors R19, R3 and R4. The potentiometerR19 serves to limit the range of travel of actuator 58 for a given rangeof travel of the master potentiometer R50. As stated above, thisfunction was provided by potentiometers R3 and R4 of electronic controlcircuit 79 of FIG. 3. The actuating arm 96 of potentiometer R19 iselectrically connected to the negative side of power supply 80a throughresistor R7a. A second difference is that a zener diode D2 has beenadded, which diode is electrically connected intermediate variableresistor R10 and input terminal 1 of the operational amplifier 90.Thirdly, resistors R16 and R17 and capacitors C3 and C4 have beeneliminated along with resistor R18. Finally, electromagnetic relays K3and K4 have been eliminated so that the electronic circuit controls onlyone reversible direct current motor which as shown in FIG. 5 is thethrottle reversible motor 54.

In operation, when the throttle lever 68 is maintained in its idleposition equal voltages appear across potentiometers R5 and R6 which asin the case of electronic control circuit 79 causes transistors 01, Q2,Q3 and O4 to be off which in turn maintains electromagnetic relays K1and K2 is their de-energized state so that reversible motor 54 isde-energized. When the throttle lever is forwardly moved, the voltageacross potentiometer R5 increases so that reversible motor 54 isforwardly driven causing actuator 58 to drive throttle arm 21 asdescribed with respect to FIG. 1. The motor 54 is de-energized when thevoltage across potentiometer R6 goes to a value such that thedifferential input signal appearing at the input of operationalamplifier 90 is equal to zero as in the case of circuit 79. Thereversible direct current motor 54 may be reversed in the same manner asdescribed with respect to the electronic control circuit 79.

It is to be understood that a circuit equivalent to that described withrespect to FIG. 5 is provided for the throttle arm 21a and is actuatedin the same manner by throttle lever 1580.

Turning to FIG. 6, an electronic control circuit 100 for controlling theengageable clutch member as described in FIG. 1 is connected across al2-volt direct current power supply 102. The electronic control circuit100 includes a wafer shaped switch 104 which is mechanically coupled tothe clutch actuating motor 60, of the clutch motor assembly 36 so as tofunction as described below. The wafer switch 104 has two conductiveportions 106a and l06b each of which substantially comprises arespective half of the wafer switch. The conductive portions may be madefrom copper or like conductive material. The wafer also has two wedgeshaped insulating or nonconductive portions 108a and 108b each of whichextends from an opposite outer edge of the wafer and meets at the centerthereof. The nonconductive portions separate the two conductive portions106a and 106k.

The electronic control circuit 100 also includes a threeposition switch110 having three positions indicated by the letters F, N and Rrespectively and a movement arm indicated by the numeral 112. The pointabout which movement arm 112 pivots is electrically connected to thenegative side of power supply 102 through a switch 114 and a timingswitch 116. The switches 114 and 116 are operably connected to thethrottle lever 68 by means not shown and function in a manner describedbelow. The F or forward position of switch 110 is slideably andelectrically connected to the wafer switch 104 by tap member 118. Thetap 118 is positioned adjacent the lower left hand quadrant of waferswitch 104 as viewed in FIG. 6 such that the tap maintains contact withthe wafer switch when the wafer switch is rotated as described below.The R or reverse position of switch 110 is connected to the lower rightquadrant of wafer switch 104 by tap member 120 in the same manner asdescribed with respect to tap member 118. The N position of switch 110is likewise slidably and electrically connected to the wafer switch 104by tap member 122. The tap member 122 is positioned on the wafer switchintermediate taps 118 and 120.

The electronic circuit 100 also includes electromagnetic relays K5 andK6 each of which has one end connected to the positive side of powersupply 102. The otherwise free side of electromagnetic relay K5 isslideably and electrically connected to wafer switch 104 by tap member124 at a point adjacent to tap member 118. The otherwise free side ofelectromagnetic relay K6 is likewise connected to wafer switch 104 bytap member 126 which is positioned adjacent tap member 120. Each of theelectromagnetic relays, K5 and K6, have respective contacts K5 and K6which are connected respectively to the forward and reverse sides ofreversible direct current motor 60, reversible direct motor 60 being themotor for controlling the engageable clutch member 30 as described inFIG. 1. The contacts K5 and K6 connect reversible motor 60 to groundwhen their respective electromagnetic relays are de-energized. This isindicated by a solid line representation of K5 and K6 in FIG. 6. Thedotted line representation of contacts K5 and K6 indicate the positionsof these contacts when their respective electromagnetic relays areenergized and will control reversible motor 60 as described below.

In operation, when the clutch lever is positioned such that engine 18and outboard drive unit 20 are disengaged as described with respect toFIG. 1, switch 110 which is mechanically coupled to clutch lever 70 ispositioned in its N position as seen in FIG. 6. This disconnects bothelectromagnetic relays K5 and K6 from power supply 102. As seen in FIG.6 the wafer switch 104 is positioned such that its nonconductive portion10% is in contact with tap member 122.

When it is desired to forwardly engage engine 18 and outboard drive unit20 the clutch lever 70 is positioned such that switch 110 is in its Fposition. This closes the circuit through electromagnetic relay K5 suchthat the current from power supply 102 will pass through electromagneticrelay 1(5 and thereafter to the negative side of the power supplythrough tap member 124, conductive portion 106a of wafer switch 104 andtap member 118, energizing electromagnetic relay 16. This is, of course,assuming that switch 114 and 116 are closed. These switches are coupledto throttle lever 68, by means not shown, such that switch 114 is closedonly when the throttle lever is in its idle position and switch 116 isenergized at the same time so as to close its contact a predeterminedperiod of time after the throttle lever has been positioned in its idleposition. The reason for the time delay is so that the engine 18 candrop back to its idle speed before actual shifting takes place.

With electromagnetic relay K5 energized contact K5 is positioned, asindicated in dotted lines so as to connect the forward side ofreversible motor 60 to a 12 volt power supply. This drives reversiblemotor 60 forwardly, as described in FIG. 1, for forwardly engagingengine 18 and outboard drive unit 20. As the motor 60 is forwardlydriven, the motor drives its mechanically connected wafer switch 104 soas to move in a counterclockwise direction as viewed in FIG. 6 untilnon-conductive portion 108a encompasses tap members 118 and 124. Thisdisconnects the circuit through electromagnetic relay K5, de-energizingelectromagnetic relay K5 and reversible motor If it is desired toreversely engage engine 18 and outboard drive unit 20, clutch lever 70is moved such that switch 110 is in its R position for energizingelectromagnetic relay K6. In such a position, current from power supply102 passes through electromagnetic relay K6, tap member 126, conductiveportion 106a of wafer switch 104 which is now positioned under taps 120and 126, tap member 120 and ultimately to the negative side of powersupply 102. This again is assuming that throttle lever 68 is positionedsuch that switches 114 and 116 are closed. With electromagnetic relay K6energized, contact K6 is positioned as indicated in dotted lines suchthat reversible motor 60 is reversely driven by the 12 volt power supplyfor appropriately driving mechanical clutch member 30 as described withrespect to FIG. 1.

As motor 60 is reversely driven, wafer switch 104 is driven clockwise.When nonconductive portion 108b encompasses tap members 120 and 126, thecircuit through electromagnetic relay K6 is again opened de-energizingK6 and reversible motor 60. The engine 18 and outboard drive unit 20 arenow reversely engaged.

If it is finally desired to disengage the engine and drive unit, clutchlever 70 is appropriately positioned such that switch 110 is again inits N position so as to energize electromagnetic relay K5. In thissituation the current from power supply 102 passes throughelectromagnetic relay K5, tap member 124, conductive portion 106 ofwafer switch 104 which now is positioned under the tap members 118, 122and 124, tap member 122 and thereafter to the negative side of powersupply 102. This ultimately causes the wafer switch again to be drivencounterclockwise until nonconductive portion l08b is positioned undertap member 122 for disconnecting the switch.

It is to be understood that an electronic control switch circuit similarto that described with respect to FIG. 6 is provided for the clutchcontrols of inboard--outboard drive system 14 and actuated by clutchlever 70a.

While a particular embodiment of the invention has been shown, it shouldbe understood, of course, that the invention is not limited theretosince many modifications may be made, and it is, therefore, contemplatedto cover by the appended claims any such modifications that fall withinthe true spirit and scope of the invention.

What is claimed is:

1. A control circuit for steering a boat powered by engine meansincluding an engine and a drive unit, said drive unit being pivotalabout an upstanding axis and having propeller means, said controlcircuit comprising: a source of electrical power; adjustable inputcircuit means electrically connected across said source of power fordeveloping a variable differential signal; means for varying saiddifferential signal from a predetermined value; an operational amplifiercircuit electrically connected to the output of said input circuit meansfor amplifying said variable differential signal; and circuit switchingmeans electrically connected to the output of said amplifier circuit andoperatively connected to said drive unit, said circuit switching meansresponsive to a variation from said predetermined differential signalfor pivoting said drive unit about said axis whereby steering of saidboat is accomplished 2. A control circuit according to claim 1 whereinsaid input circuit means includes a first variable resistor electricallyconnected across said source of power for developing a first voltage; asecond variable resistor electrically connected across said firstresistor for developing a second voltage; means electrically connectedto said first and second resistors, combining said first and secondvoltages for developing said differential signal; means electricallyconnected to said first resistor for varying said first voltage therebyvarying said differential signal from said predetermined value wherebysaid drive unit is pivoted about said axis; and means electricallyconnected to said second resistor and operatively connected to saiddrive unit whereby the pivoting of said drive unit varies said secondvoltage proportional to the variation of said first voltage forrestoring the differential signal to said predetermined value andstopping said drive unit.

3. A control circuit according to claim 2 including reversible motormeans electrically connected to said circuit switching means andoperatively connected to said drive unit for pivoting said drive unit,said motor means being responsive to a positive variation from saidpredetermined value for pivoting said drive unit in one direction andresponsive to a negative variation from said predetermined value forpivoting said drive unit in an opposite direction.

4. A control system for steering a boat powered by engine meansincluding an engine and a drive unit, said drive unit being pivotalabout an upstanding axis and having propeller means, said controlcircuit comprising: a source of electrical power, a resistance bridgecircuit having first and second variable resistance elements, anoperational amplifier having first and second input terminals forreceiving electrical signals from said first and second variableresistance elements respectively, and further having an output terminalfor producing a predetermined reference potential when the electricalsignals from said first and second variable resistance elements are thesame value and for producing a potential different than said referencepotential when the electrical signals from said first and secondvariable resistance elements are of different values, first and secondswitch circuit means coupled to the output of said operationalamplifier, said first switch circuit means being responsive when thepotential at the output terminal of said operational amplifier is abovesaid reference potential and said second switch circuit means beingresponsive when the potential at the output of said operationalamplifier is below said reference potential, and motor means operativelyconnected to said drive unit and responsive to said first and secondswitch circuit means for pivoting said drive unit about said upstandingaxis for steering the boat,

5. The control system according to claim 4 further including first andsecond transistors of opposite conducting types with their emitters tiedtogedier and their collectors connected across said source of electricalpower, the output terminal of said operational amplifier being connectedto the base electrodes of said first and second transistors, a secondreference potential connected to the emitters of said first and secondtransistors, said second reference potential being substantially equalto the reference potential developed at the output terminal of saidoperational amplifier thereby maintaining said first and secondtransistors non-conductive, whereby a decrease in the referencepotential at the output terminal of said operational amplifier willcause said first transistor to be rendered conductive and an increase inthe reference potential at the output terminal of said operationalamplifier will cause said second transistor to be rendered conductive tooperate said first and second switch circuit means, respectively.

6. In a control system for a boat, the combination including, levermeans, motor means operatively connected to said lever means to actuatethe same for controlling a function of the boat for maneuvering, asource of electrical power, a resistance bridge circuit having first andsecond variable resistance elements connected across said source ofelectrical power, an operational amplifier having first and secondinputs for receiving electrical signals from said first and secondvariable resistance elements respectively, and further having an outputfor producing a predetermined reference potential when the electricalsignals from said first and second variable resistance elements are ofthe same value and for producing a potential different than saidreference potential when the electrical signals from said first andsecond variable resistance elements are of a different value, first andsecond switch circuit means coupled to the output of said operationalamplifier, said first switch circuit means being responsive when thepotential at the output of said operational amplifier is above saidreference potential and said second switch circuit means beingresponsive when the potential at the output of said operationalamplifier is below said reference potential, and means connecting saidswitch means to said motor means for operating the same in one or theother direction, depending on which switch means is actuated, for movingsaid lever means.

Ina/n n...

equal to the reference potential developed at the output of saidoperational amplifier thereby maintaining said first and secondtransistors non-conductive, whereby a decrease in the referencepotential at the output of said operational amplifier will cause saidfirst transistor to be rendered conductive and an increase in thereference potential at the output of said operational amplifier willcause said second transistor to be rendered conductive to operate saidfirst and second switch circuit means, respectively.

1. A control circuit for steering a boat powered by engine meansincluding an engine and a drive unit, said drive unit being pivotalabout an upstanding axis aNd having propeller means, said controlcircuit comprising: a source of electrical power; adjustable inputcircuit means electrically connected across said source of power fordeveloping a variable differential signal; means for varying saiddifferential signal from a predetermined value; an operational amplifiercircuit electrically connected to the output of said input circuit meansfor amplifying said variable differential signal; and circuit switchingmeans electrically connected to the output of said amplifier circuit andoperatively connected to said drive unit, said circuit switching meansresponsive to a variation from said predetermined differential signalfor pivoting said drive unit about said axis whereby steering of saidboat is accomplished.
 2. A control circuit according to claim 1 whereinsaid input circuit means includes a first variable resistor electricallyconnected across said source of power for developing a first voltage; asecond variable resistor electrically connected across said firstresistor for developing a second voltage; means electrically connectedto said first and second resistors, combining said first and secondvoltages for developing said differential signal; means electricallyconnected to said first resistor for varying said first voltage therebyvarying said differential signal from said predetermined value wherebysaid drive unit is pivoted about said axis; and means electricallyconnected to said second resistor and operatively connected to saiddrive unit whereby the pivoting of said drive unit varies said secondvoltage proportional to the variation of said first voltage forrestoring the differential signal to said predetermined value andstopping said drive unit.
 3. A control circuit according to claim 2including reversible motor means electrically connected to said circuitswitching means and operatively connected to said drive unit forpivoting said drive unit, said motor means being responsive to apositive variation from said predetermined value for pivoting said driveunit in one direction and responsive to a negative variation from saidpredetermined value for pivoting said drive unit in an oppositedirection.
 4. A control system for steering a boat powered by enginemeans including an engine and a drive unit, said drive unit beingpivotal about an upstanding axis and having propeller means, saidcontrol circuit comprising: a source of electrical power, a resistancebridge circuit having first and second variable resistance elements, anoperational amplifier having first and second input terminals forreceiving electrical signals from said first and second variableresistance elements respectively, and further having an output terminalfor producing a predetermined reference potential when the electricalsignals from said first and second variable resistance elements are thesame value and for producing a potential different than said referencepotential when the electrical signals from said first and secondvariable resistance elements are of different values, first and secondswitch circuit means coupled to the output of said operationalamplifier, said first switch circuit means being responsive when thepotential at the output terminal of said operational amplifier is abovesaid reference potential and said second switch circuit means beingresponsive when the potential at the output of said operationalamplifier is below said reference potential, and motor means operativelyconnected to said drive unit and responsive to said first and secondswitch circuit means for pivoting said drive unit about said upstandingaxis for steering the boat.
 5. The control system according to claim 4further including first and second transistors of opposite conductingtypes with their emitters tied together and their collectors connectedacross said source of electrical power, the output terminal of saidoperational amplifier being connected to the base electrodes of saidfirst and second transistors, a second referEnce potential connected tothe emitters of said first and second transistors, said second referencepotential being substantially equal to the reference potential developedat the output terminal of said operational amplifier thereby maintainingsaid first and second transistors non-conductive, whereby a decrease inthe reference potential at the output terminal of said operationalamplifier will cause said first transistor to be rendered conductive andan increase in the reference potential at the output terminal of saidoperational amplifier will cause said second transistor to be renderedconductive to operate said first and second switch circuit means,respectively.
 6. In a control system for a boat, the combinationincluding, lever means, motor means operatively connected to said levermeans to actuate the same for controlling a function of the boat formaneuvering, a source of electrical power, a resistance bridge circuithaving first and second variable resistance elements connected acrosssaid source of electrical power, an operational amplifier having firstand second inputs for receiving electrical signals from said first andsecond variable resistance elements respectively, and further having anoutput for producing a predetermined reference potential when theelectrical signals from said first and second variable resistanceelements are of the same value and for producing a potential differentthan said reference potential when the electrical signals from saidfirst and second variable resistance elements are of a different value,first and second switch circuit means coupled to the output of saidoperational amplifier, said first switch circuit means being responsivewhen the potential at the output of said operational amplifier is abovesaid reference potential and said second switch circuit means beingresponsive when the potential at the output of said operationalamplifier is below said reference potential, and means connecting saidswitch means to said motor means for operating the same in one or theother direction, depending on which switch means is actuated, for movingsaid lever means.
 7. The control system according to claim 6 furtherincluding first and second transistors of opposite conductivity typewith their emitters tied together and their collectors connected acrosssaid source of electrical power, the output of said operationalamplifier being connected to the base electrodes of said first andsecond transistors, a second reference potential connected to theemitters of said first and second transistors, said second referencepotential being substantially equal to the reference potential developedat the output of said operational amplifier thereby maintaining saidfirst and second transistors non-conductive, whereby a decrease in thereference potential at the output of said operational amplifier willcause said first transistor to be rendered conductive and an increase inthe reference potential at the output of said operational amplifier willcause said second transistor to be rendered conductive to operate saidfirst and second switch circuit means, respectively.